Many applications require the controlled propagation of optical waves like those in planar waveguides, photonic integrated circuits, light sources, such as lasers, and detectors to be coupled into an optical fiber. Still other applications require the coupling of one optical fiber to another optical fiber. Unfortunately, many of these applications are subject to disadvantages and may require a high degree of care in fabrication.
For example, a direct attachment of an optical fiber to the laser can be disrupted, because the operating temperature of the laser will fluctuate and cause different dimensional changes respectively in the fiber and the laser. The dimensional changes in response to temperature fluctuation will cause the fiber to change position with respect to the laser or become separated from the laser.
Direct coupling is generally inefficient because of a wide disparity in the dimensions of the guided modes in the laser and in the fiber. This inefficiency is generally overcome by the use of a lens or lens group to focus optical emission from a laser into an optical fiber.
However, optical coupling is subject to further disadvantages arising from the use of the lens or lens group. For example, it is difficult to achieve precision optical alignment of the lens and the laser. The fiber can become misaligned due to dimensional changes and mechanical drifts with environmental temperature fluctuations over time. Consequently, there is a need for an improved method of optical fiber formation, which can improve optical fiber coupling.